Over a century ago, Charles Booth’s surveyors were colouring in large-scale maps of London according to their estimate of each street’s level of poverty and moral standing. Booth came up with seven classes, but by then the British had grown used to thinking of themselves as having three – working, middle and upper – as formulated by Marx in the 1840s (though this had in fact already been anticipated by British labour and radical movements two decades earlier). The 1911 census added occupation and infant mortality to the measure and the 1921 census presented five classes, but three remained the basic number (with all sorts of barnacles) until the 1950s, when sociologists broke the model by asking it to bear social mobility and affluent workers as well. Prominent left-wing commentators and comedians continue to talk in terms of three classes, with an overarching and slightly ridiculous landed Tory Establishment at the top and a long-suffering, food-bank-dependent proletariat at the bottom, but really it’s not much of a reflection of how things are for most of us.